U.S. patent number 10,547,225 [Application Number 16/214,540] was granted by the patent office on 2020-01-28 for method for producing an electric motor with stator having step-shaped stator teeth.
This patent grant is currently assigned to MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD.. The grantee listed for this patent is MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD.. Invention is credited to Masahiko Asai, Makoto Hattori, Kazuki Niwa.
United States Patent |
10,547,225 |
Hattori , et al. |
January 28, 2020 |
Method for producing an electric motor with stator having
step-shaped stator teeth
Abstract
A method for producing an electric motor provided with a stator
core configured by laminating a required number of annular
electromagnetic steel sheets having a plurality of tooth portions
on an inner periphery thereof. The circumferential widths of the
tooth portions become gradually narrower in a stepwise fashion
toward an uppermost surface and an undermost surface of the
plurality of laminated electromagnetic steel sheets, whereby the
shoulder portions on both sides in a circumferential direction of
the tooth portions smoothly change. A flexible, planar insulating
member is provided having a first portion of a shape similar to a
planar shape of said electromagnetic steel sheet, and further
comprising flexible ear portions at positions corresponding to
shoulder portions on both sides in a circumferential direction of
the tooth portions. A coil is wound around the flexible planar
insulating member and the respective tooth portions, including the
ear portions of said insulating member interposed between the coil
winding and the tooth portion, to thereby deform the flexible ear
portions to conform the shape of the shoulder portions.
Inventors: |
Hattori; Makoto (Tokyo,
JP), Asai; Masahiko (Tokyo, JP), Niwa;
Kazuki (Tokyo, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
MITSUBISHI HEAVY INDUSTRIES THERMAL SYSTEMS, LTD. |
Tokyo |
N/A |
JP |
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Assignee: |
MITSUBISHI HEAVY INDUSTRIES THERMAL
SYSTEMS, LTD. (Tokyo, JP)
|
Family
ID: |
49881723 |
Appl.
No.: |
16/214,540 |
Filed: |
December 10, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190181711 A1 |
Jun 13, 2019 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14394776 |
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PCT/JP2013/061895 |
Apr 23, 2013 |
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Foreign Application Priority Data
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Jul 4, 2012 [JP] |
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2012-150640 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K
3/345 (20130101); H02K 3/48 (20130101); H02K
1/146 (20130101); H02K 1/185 (20130101); H02K
2213/03 (20130101); H02K 21/16 (20130101) |
Current International
Class: |
H02K
3/34 (20060101); H02K 1/14 (20060101); H02K
1/18 (20060101); H02K 3/48 (20060101); H02K
21/16 (20060101) |
Field of
Search: |
;310/215,216.115,216.105,216.61,43,194,214,216.023,216.011,216.018,216.019,216.216,216.061
;29/596 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1567679 |
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Jan 2005 |
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CN |
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101523696 |
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Sep 2009 |
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CN |
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8-275423 |
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Oct 1996 |
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JP |
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2001-178031 |
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Jun 2001 |
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JP |
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2004-135382 |
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Apr 2004 |
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JP |
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2004-242443 |
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Aug 2004 |
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JP |
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2004-248440 |
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Sep 2004 |
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JP |
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2005-45884 |
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Feb 2005 |
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JP |
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2005-95000 |
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Apr 2005 |
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JP |
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2007-215335 |
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Aug 2007 |
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JP |
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2008-206322 |
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Sep 2008 |
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JP |
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2010-130842 |
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Jun 2010 |
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JP |
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4788881 |
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Oct 2011 |
|
JP |
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Other References
Chinese Office Action and Search Report, dated Mar. 30, 2016, for
Chinese Application No. 201380021267.2, together with an English
translation thereof. cited by applicant .
Chinese Office Action dated Nov. 23, 2016 in corresponding Chinese
Patent Application No. 201380021267.2 with an English Translation.
cited by applicant.
|
Primary Examiner: Lian; Mang Tin Bik
Assistant Examiner: Almawri; Maged M
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP.
Parent Case Text
This application is a Continuation of copending application Ser.
No. 14/394,776, filed on Oct. 16, 2014, which is the National Phase
under 35 U.S.C. .sctn. 371 of International Application No.
PCT/JP2013/061895, filed on Apr. 23, 2013, which claims the benefit
under 35 U.S.C. .sctn. 119(a) to Patent Application No.
2012-150640, filed in Japan on Jul. 4, 2012, all of which are
hereby expressly incorporated by reference into the present
application.
Claims
The invention claimed is:
1. A method for producing an electric motor, the electric motor
comprising: a stator core comprising a plurality of laminated
annular electromagnetic steel sheets having an annular portion and
a plurality of tooth portions on an inner periphery side, and a
coil winding wound about each tooth portion, wherein the
electromagnetic steel sheet has a continuous plane formed from the
annular portion and the tooth portions and wherein the
circumferential widths of the tooth portions of the plurality of
laminated electromagnetic steel sheets become gradually narrower in
width in a stepwise fashion toward an uppermost surface and an
undermost surface of the plurality of laminated electromagnetic
steel sheets, whereby shoulder portions on both sides in a
circumferential direction of the tooth portions smoothly change,
the method comprising providing a flexible, planar insulating
member having a first portion of a shape similar to the annular
portion of said electromagnetic steel sheet and a second portion of
a shape similar to the tooth portions, said planar insulating
member further comprising flexible ear portions at positions
corresponding to the shoulder portions on both sides in the
circumferential direction of the tooth portions, and the first
portion, the second portion and the ear portion forming a
continuous plane, and winding the coil winding around the flexible
planar insulating member and the respective tooth portions,
including the ear portions of said insulating member interposed
between the coil winding and the tooth portion, to thereby deform
the flexible ear portions to conform the shape of the shoulder
portions.
2. The method according to claim 1, comprising providing said
flexible, planar insulating member on the uppermost surface and on
the undermost surface of the plurality of laminated electromagnetic
steel sheets of the stator.
3. The method according to claim 1, wherein said insulating member
is an insulative film.
4. The method according to claim 1, wherein said insulating member
has a thickness that is less than or equal to 1 mm.
Description
TECHNICAL FIELD
The present invention relates to an electric motor in which it is
possible to attain a reduction in size by making the axial
dimension of a stator small.
BACKGROUND ART
A direct winding motor is used in an electric motor for a
compressor which is applied to a refrigerant compressor of an
in-car air conditioner. In the direct winding motor, coil bobbins
having insulation properties are installed at tooth portions around
which a coil winding is wound, on both end sites of a stator core
which is configured by laminating a required number of
electromagnetic steel sheets generally shaped by punching, and the
coil winding is then wound (refer to, for example, PTL 1).
On the other hand, PTL 2 discloses a stator of an electric motor in
which a stator core is configured to be divided into a plurality of
split core bodies a, in each of which a tooth portion and a yoke
portion are integrally formed, and a plurality of split core bodies
b each forming a yoke portion which is pinched by the split core
bodies a, and a coil winding is directly wound around the tooth
portion of the split core body a without mounting a winding guide
(a coil bobbin).
CITATION LIST
Patent Literature
[PTL 1] Japanese Patent No. 4788881
[PTL 2] Japanese Unexamined Patent Application Publication No.
2005-95000
SUMMARY OF INVENTION
Technical Problem
However, in the case of the motor in which the coil bobbins are
installed at both end sites of the stator core, as shown in PTL 1,
since the coil bobbin itself has a thickness dimension, the axial
dimension of a stator increases by an amount equivalent to the
thickness dimension, thereby causing one of factors in an increase
in the size of the motor. For this reason, in the motor having the
coil bobbin, as an electric motor for a compressor in which an
improvement in the ability to be mounted on a vehicle by a
reduction in size is required, the request cannot be sufficiently
satisfied.
On the other hand, in a structure rendering coil bobbin-less, as
shown in PTL 2, the axial dimension of a stator is reduced by an
amount corresponding to the thickness dimension of a coil bobbin,
and thus it is considered that it is possible to reduce the size of
the motor. However, in a structure rendering only coil bobbin-less,
there is a concern that a problem such as coating damage or
disconnection of the coil winding may occur at the time of winding
due to edges which are formed at shoulder portions on both sides in
a circumferential direction of the tooth portion around which the
coil winding is wound, of the stator core which is configured by
laminating the electromagnetic steel sheets shaped by punching, and
thus there is a case where the quality of the coil winding cannot
be secured.
The present invention has been made in view of such circumstances
and has an object to provide an electric motor in which even if
coil bobbin-less is rendered, coating damage, disconnection, or the
like of a coil winding by a shoulder portion edge of a tooth
portion is prevented, and thus it is possible to wind the coil
winding while securing the quality thereof.
Solution to Problem
In order to solve the above-described problem, an electric motor
according to the present invention adopts the following means.
That is, according to a first aspect of the present invention,
there is provided an electric motor including: a stator core
configured by laminating a required number of annular
electromagnetic steel sheets having a plurality of tooth portions
around each of which a coil winding is wound, on an inner periphery
side, wherein circumferential widths of the tooth portion in the
plurality of electromagnetic steel sheets which are laminated on
both end sides of the stator core become gradually narrow toward
the respective end portion sides, and the coil winding is directly
wound around the tooth portion in which shoulder portions on both
sides in a circumferential direction of the tooth portion which is
formed by lamination of the electromagnetic steel sheets are
shoulder portions which smoothly change so as to narrow in width in
a stepwise fashion toward the respective end portions.
According to the electric motor related to the first aspect of the
present invention, the circumferential widths of the tooth portion
in the plurality of electromagnetic steel sheets which are
laminated on both end sides of the stator core having a laminated
structure become gradually narrow toward the respective end portion
sides and the coil winding is directly wound around the tooth
portion in which shoulder portions on both sides in a
circumferential direction of the tooth portion which is formed by
lamination of the electromagnetic steel sheets are shoulder
portions which smoothly change so as to narrow in width in a
stepwise fashion toward the respective end portions, and therefore,
even in a configuration in which coil bobbin-less is rendered, and
thus the coil winding is directly wound around the tooth portion in
the electromagnetic steel sheets, since the shoulder portions on
both sides in the circumferential direction of the tooth portion
are shoulder portions which smoothly change so as to narrow in
width in a stepwise fashion toward the end portions and have a
shape along a winding shape of the coil winding, coating damage,
disconnection, or the like of the coil winding by a shoulder
portion edge of the tooth portion is prevented, and thus it is
possible to wind the coil winding while securing the quality
thereof. Therefore, the axial dimension of a stator is reduced by
an amount equivalent to the thickness of a coil bobbin, and thus it
is possible to reduce the thickness of the motor. Further, due to
rendering coil bobbin-less, it is possible to attain the
simplification of a configuration and cost reduction, and it is
possible to attain improvement in efficiency due to a reduction in
the wire length of the coil winding, improvement in reliability due
to contact relaxation between the coil winding and the stator core,
or the like.
Further, according to a second aspect of the present invention, in
the electric motor described above, the coil winding is wound
around the tooth portion with a thin insulating member having a
shape along the shoulder portion interposed therebetween.
According to the electric motor related to the second aspect of the
present invention, the coil winding is wound around the tooth
portion with the thin insulating member having a shape along the
shoulder portion interposed therebetween, and therefore, even in a
case where due to rendering coil bobbin-less, a reduction in
insulation properties between the coil winding and the stator core
is of a concern and the amount of reduction exceeds a defined
value, it is possible to cope with it by winding the coil winding
with the interposition of the thin insulating members having a
shape along the shoulder portion. Therefore, it is possible to
attain the above-described effect by rendering coil
bobbin-less.
Further, according to a third aspect of the present invention, in
the electric motor described above, the insulating member has an
ear portion which can be deformed along a shape of the shoulder
portion of the tooth portion.
According to the electric motor related to the third aspect of the
present invention, the insulating member has the ear portion which
can be deformed along the shape of the shoulder portion of the
tooth portion, and therefore, even in a case of winding the coil
winding with the interposition of the insulating member, it is
possible to wind the coil winding around the tooth portion with the
insulating member interposed therebetween, while deforming the ear
portion provided at the insulating member so as to follow the shape
of the shoulder portion of the tooth portion. Therefore, it is
possible to wind the coil winding while securing the quality so as
to follow the shape of the shoulder portion of the tooth portion,
regardless of the presence or absence of the insulating member.
Further, according to a fourth aspect of the present invention, in
any one of the electric motors described above, the insulating
member is configured with an insulating sheet having flexibility
and having a shape similar to a planar shape of the electromagnetic
steel sheet.
According to the electric motor related to the fourth aspect of the
present invention, the insulating member is configured with the
insulating sheet having flexibility and having a shape similar to
the planar shape of the electromagnetic steel sheet, and therefore,
when winding the coil winding with the interposition of the
insulating member, by laminating the insulating sheets having a
similar shape to the electromagnetic steel sheet on both ends of
the stator core and winding the coil winding thereon, it is
possible to wind the coil winding so as to follow the shape of the
shoulder portion of the tooth portion while bending and deforming
the insulating sheets having flexibility so as to follow the shape
of the shoulder portion of the tooth portion. Therefore, it is
possible to reliably wind the coil winding while securing the
quality thereof, without impairing the workability of winding work
of the coil winding.
Advantageous Effects of Invention
According to the present invention, even in a configuration in
which coil bobbin-less is rendered, and thus the coil winding is
directly wound around the tooth portion in the electromagnetic
steel sheets, since the shoulder portions on both sides in the
circumferential direction of the tooth portion are shoulder
portions which smoothly change so as to narrow in width in a
stepwise fashion toward the end portions and have a shape along a
winding shape of the coil winding, coating damage, disconnection,
or the like of the coil winding by a shoulder portion edge of the
tooth portion is prevented, and thus it is possible to wind the
coil winding while securing the quality thereof. For this reason,
the axial dimension of the stator is reduced by an amount
equivalent to the thickness of the coil bobbin, and thus it is
possible to reduce the thickness of the motor. Further, due to
rendering coil bobbin-less, it is possible to attain the
simplification of a configuration and cost reduction, and it is
possible to attain improvement in efficiency due to a reduction in
the wire length of the coil winding, improvement in reliability due
to contact relaxation between the coil winding and the stator core,
or the like.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a plan view of an electric motor according to an
embodiment of the present invention in a state where a coil winding
is omitted.
FIG. 2 is a perspective view of a tooth portion of a stator core of
the electric motor shown in FIG. 1.
FIG. 3 is a plan view of the tooth portion of the stator core shown
in FIG. 2.
FIG. 4 is a diagram equivalent to the cross-section along line A-A
of FIG. 3.
FIG. 5 is a partial plan view of an insulating sheet which is used
in a case where insufficient insulation is of a concern.
FIG. 6A is a schematic diagram of an embodiment in which a coil
bobbin is used; and
FIG. 6B is a schematic diagram of an embodiment in which coil
bobbin-less is rendered according to the change of the tooth
portion.
DESCRIPTION OF EMBODIMENTS
Hereinafter, an embodiment of the present invention will be
described with reference to FIGS. 1 to 6.
In FIG. 1, a plan view of an electric motor according to an
embodiment of the present invention in a state where a coil winding
is omitted is shown.
An electric motor 1 is configured to include a stator 2 which is
configured by winding a coil winding (not shown) around a tooth
portion 4 of a stator core 3 having an annular shape, and a rotor
10 which is rotatably disposed inside the stator 2 with a
predetermined gap interposed therebetween.
The rotor 10 has a cylindrical rotor core 11 which is configured by
laminating a required number of thin electromagnetic steel sheets
shaped by punching, and a through-hole 12 into which a rotating
shaft (not shown) is fitted is axially bored in a central portion
thereof. In the rotor core 11, holes for magnet embedment 13 in a
number corresponding to the number of poles (in this embodiment,
six poles) of a motor are provided so as to surround the
through-hole 12 along an outer peripheral site thereof, and a
configuration is made in which a permanent magnet 14 is embedded in
each of the holes 13.
The stator core 3 configuring the stator 2 is configured by
laminating a required number of electromagnetic steel sheets 5
shaped in an annular shape by punching, and the tooth portion 4 for
winding a coil winding therearound is provided on the inner
periphery side thereof. In the case of this embodiment, the tooth
portions 4 are provided at nine places at substantially equal
intervals on the inner periphery side of the stator core 3, and a
slot 6 is punched between the respective tooth portions 4, whereby
the coil winding can be wound around the tooth portion 4. In the
case of this embodiment, a configuration is made in which coil
windings of three phases, a U-phase, a V-phase, and a W-phase, are
sequentially wound at three places.
The tooth portion 4 is configured such that circumferential widths
B of the tooth portion 4 in the plurality of electromagnetic steel
sheets 5 which are laminated on both end sides of the stator core 3
are shaped by punching such that the widths B become gradually
narrow toward the respective end portion sides E, and shoulder
portions 7 which are formed on both sides in a circumferential
direction of the tooth portion 4 on both end sides of the stator
core 3 when the electromagnetic steel sheets 5 are laminated form
the shoulder portions 7 which smoothly change so as to narrow in
width in a stepwise fashion toward the respective end portions, as
shown in FIGS. 2 to 4.
As described above, a configuration is made in which the shoulder
portions 7 which are formed on both sides in the circumferential
direction of the tooth portion 4 around which the coil winding of
the stator core 3 is wound form the shoulder portions 7 which
smoothly change so as to narrow in width in a stepwise fashion
toward the respective end portions, on both end portion sides of
the stator core 3. In this manner, even if coil bobbin-less is
rendered, and thus the coil winding is directly wound around the
tooth portion 4, the shoulder portions 7 of the tooth portion 4
have a smooth shape along a winding shape of the coil winding. For
this reason, the coil winding is not subjected to coating damage or
disconnection by a shoulder portion edge of the tooth portion 4,
and thus it is possible to wind the coil winding while securing the
quality thereof.
For this reason, an axial dimension of the stator 2 is reduced by
an amount equivalent to the thickness of a coil bobbin which
generally is a resin molded product and in which a central portion
is thick compared to both side portions, and thus it is possible to
make the motor thinner. Further, due to rendering coil bobbin-less,
it is possible to attain the simplification of a configuration and
cost reduction, and it is possible to attain improvement in
efficiency due to a reduction in the wire length of the coil
winding, improvement in reliability due to contact relaxation
between the coil winding and the stator core 3, or the like.
A schematic diagram in which a structure in a case FIG. 6A where a
coil bobbin is used is compared with a structure in a case FIG. 6B
in which coil bobbin-less is rendered according to the change of
the tooth portion 4 is shown.
In a case where a coil winding is wound around a tooth portion 4A
with a coil bobbin 20 interposed therebetween, an axial dimension L
of the stator 2 which includes the coil winding is increased by an
amount equivalent to the thickness of the coil bobbin 20. In
contrast, by making the shoulder portions 7 on both sides in the
circumferential direction of the tooth portion 4 be the shoulder
portions 7 which smoothly change so as to narrow in width in a
stepwise fashion toward the end portion side, and directly winding
the coil winding, thereby omitting the coil bobbin 20, it is
possible to shorten the dimension L by at least an amount
equivalent to the thickness of the coil bobbin 20. For this reason,
it is possible to expect the effects such as the thinning of the
motor, the simplification of a configuration, cost reduction, and
improvement in efficiency due to a reduction in winding wire
length.
On the other hand, as described above, in a case where insulation
performance between the stator core 3 and the coil winding is
reduced due to rendering coil bobbin-less and the amount of
reduction exceeds a defined value, thin insulating members 8 may be
disposed at both ends of the tooth portion 4 of the stator core 3.
As the insulating member 8, it is possible to use an insulating
sheet, an insulative film, or a molded product by vacuum molding,
injection molding, or the like. However, in order to attain the
effect by rendering coil bobbin-less, it is preferable to make the
thickness of the insulating member 8 be less than or equal to 1
mm.
In FIG. 5, an example in which an insulating sheet having
flexibility and having a planar shape similar to the shape of the
electromagnetic steel sheet 5 shaped in an annular shape by
punching is used as the insulating member 8 is shown. In the case
of the insulating sheet 8, the insulating sheets are used to be
laminated on both end surfaces of the stator core 3. However, a
configuration is adopted in which car portion 9 having an
appropriate length are provided at positions corresponding to the
shoulder portions 7 so as to be deformed along the smooth shoulder
portions 7 on both sides in the circumferential direction of the
tooth portion 4.
In this manner, in a case where a reduction in insulation
properties between the coil winding and the stator core 3 is of a
concern, it is possible to cope with it by winding the coil winding
with the thin insulating member 8 having a shape along the shoulder
portion interposed therebetween. Even in this case, by using the
insulating member 8 having a thickness less than or equal to 1 mm,
it is possible to attain the above-described effect by rendering
coil bobbin-less. Further, by using the insulating member (the
insulating sheet) 8 having the ear portion 9 which can be deformed
along the shape of the smooth shoulder portion 7 of the tooth
portion 4, it is possible to wind the coil winding around the tooth
portion 4 with the insulating member 8 interposed therebetween,
while deforming the ear portion 9 so as to follow the shape of the
shoulder portion 7 of the tooth portion 4. For this reason, it is
possible to wind the coil winding while securing quality so as to
follow the shape of the shoulder portion 7, regardless of the
presence or absence of the insulating member 8.
Furthermore, when the insulating member 8 is configured with the
insulating sheet having flexibility and having a shape similar to
the planar shape of the electromagnetic steel sheet 5 and the coil
winding is wound with the interposition of the insulating member
(the insulating sheet) 8, the insulating sheets having a similar
shape to the electromagnetic steel sheet 5 are laminated on both
ends of the stator core 3 and the coil winding is wound thereon. In
this way, it is possible to wind the coil winding so as to follow
the shape of the shoulder portion of the tooth portion 4 while
bending and deforming the insulating sheet 8 having flexibility so
as to follow the shapes of the shoulder portions 7 of the tooth
portion 4. For this reason, it is possible to wind the coil winding
while securing the quality thereof, without impairing the
workability of winding work of the coil winding.
In addition, the present invention is not limited to an invention
related to the above-described embodiment, and modifications can be
appropriately made within a scope which does not depart from the
gist of the present invention. For example, in the above-described
embodiment, the number of electromagnetic steel sheets 5 which
gradually narrow the circumferential width B of the tooth portion 4
is not particularly defined. However, the number of electromagnetic
steel sheets 5 may be appropriately determined by the extent the
shoulder portion 7 is made smooth, in consideration of the size of
the circumferential width dimension of the tooth portion 4, the
sheet thickness of the electromagnetic steel sheet 5, the thickness
of the coil winding, or the like, and the number is changed
according to the size, the output, and other characteristics of an
electric motor.
REFERENCE SIGNS LIST
1: electric motor 3: stator core 4: tooth portion 5:
electromagnetic steel sheet 7: shoulder portion 8: insulating
member (insulating sheet) 9: ear portion B: circumferential width
of tooth portion
* * * * *